Furnace stoker



Patented July 16, 1946 FFICE `2,404,211 a FURNAoE sToKER v William P. Biddle,

Knoxville, Tenn.,

ford, Knoxville, Tenn. Application December 2, 1941, Serial No. 421,356 17 claims. (o1. 1ro- 109)l The invention relates generally to furnaces and has for an object to provide a novel form ofstoker mounted on the door of a furnace and effective to mechanically feed solid fuel through said door and onto the fire bed in the furnace.

Furnace door mounted /stokin-g equipments have been provided hereto-fore, but these have enjoyed only limited public approva1 because of various faults therein such as the complicated and expensive nature of their construction and operation, lack of proper control lof the actual infeeding of the solid fuel, and inability to handle large lumps or particles of fuel or foreign matter without jamming. It is the purpose of the present invention to provide an improved stoker structure in which all of these objectionable characteristics are avoided.

In its more detailed nature the invention resides in providing an improved form ofl furnace door mounted s'toker comprising a housing rigidly mounted on the door, a hopper supported on the housing and having a gravity disch-arge throat extending downwardly into the housing, said door and housing having registering openings therein adjacent the throat and communicating with the interior of the furnace, `a yieldable gate in part defining the portion of said throat nearest said openings and yieldable to permit passage o-f fuel lumps or large particles of foreign matter and to prevent excessive feeding. of fine coal from the upper part of the hopper at the time that the yieldable gate is engaged by a coal lump, and aY fuel feeding pusher reciprocable across the throat' just beneath said gate and effective upon each forward stroke to deliver a charge of fuel through said openings into the furnace.

Another object of the invention is to provide a stoker structure of the character stated in which the pusher is oscillatably mounted and includes an arcuate plate portion the are of which is struck from the center about which the pusher oscillates and which plate is effective to close the throat as the pusher moves forward, and in which the yieldable gate comprises Aa, plurality of exible spring steel vfingers having their lower ends freely suspended toa point just short of the path of movement of said plate.

Another object of the invention is to provide a stoker structure of the character stated in which a fuel supporting plate is attached to the pusher in position for forming with the pusher a pocket or supporting shelf for receiving and supporting fuel when the pusher is retracted, and movable with the pusher, when the latter is projected to deliver a charge of fuel in the furnace, to a posi- Jr., and Hugh W. Sanford, Jr., assignors to Hugh W. Sanp .2 Y tion for aiding in .the distribution of .the charge of fuel over the lire bed in the furnace;

Another object of the invention is to provide in a Stoker of the character stated a fuel supporting and distributing plate which. is pivotally connected to the pusher and so engageable with fixed supporting means as to be positioned generally horizontally as a .fuel supporting shelf beneath the yieldable gate when the pusher is retracted, and movable to a forward and downwardly inclined position extended in fuel distributing position into the interior of the furnace when the pusher is projected.

Another object of the invention is to provide in a Stoker of the character stated power operated means for slowly oscillating the fuel feeding pusher and including .a motor andcrank and link connections for transmitting the rotary motion from the motor in theformofoscillatory motion to the pusher, said connectionsalso including pawl `and ratchet wheel devices.

Another object of the invention is to `.provide in a stoker of =the character stated, :movement transmitting connections including lost motion devices effective to enable adjustment `.of the stroke imparted to the pusher without altering theforward or fuel charging stroke limit of the pusher.-

With the .above and` other objects in view vthat will hereinafter appear, the nature of the invention will be more fully understood by following the detailed description, `the appended claims, and the several views illustrated in the accom- Danying drawings.

In the drawings:

Figure 1 is a vertical cross section of a furnace with the invention mounted on the door thereof, the normal, retracted position of the pusher bein-g shown in dotted lines, ,and the fuel feeding and distributing position being illustrated in full lines.

Figure 2 is a vertical cross sectional view taken on the 4line 2-2 on Figure 1.

Figure 3 is an enlarged ,detail vertical cross l sectional view taken on the line 3--3 on Figure 1.

Figurev 4 is a detail Vertical longitudinal sectional view taken on the line 4 4 on Figure 3.

In the exemplary disclosure of the invention herein illustrated the furnace 5 embodying the usual jacketed Walls includes a re bed supporting grate 6 which is accessible through `a firing opening 1, said opening being normally closed by the usual hingedly mounted door 8. This furnace structure may be of any conventional form.

In the practical development of the invention there is provided a housing or supporting structure 9 which is securely 1 cured tothe hinged door and equipped with an opening registering with the ring opening 1 and a'n opening I0 formed in the door 8. A hopper II is supported on the housing 9 and includes a gravity discharge throat and I0. Y

The foremost wall of the hopper terminates, as

` ing 9, and this wall is supplemented by a yieldable wall or gate structure generally designated-1- I4 and composed of a rigidly mounted bar-I5 and de enclin closel s aced spring steel-fingers I6 p g y p i upon a cross rod 46 or other suitable supportmg which depend from said bar..

I2 which depends in the l housing Vvadjacent the registeringV openings` bolted or'otherwise seat I3, a short distance below the top of the heus-JQ ing I which communlcates between the discharge throat I2 and the interior of the furnace An oscillatable fuel feeder or pusheris pivotally supported, as at I1, in the housing beneath the discharge throat I2, and this pusher includes la 3 flat front plate I8 and an arcuate top plate I9,3

the arc ofthe top plate being struck from. the

center about whichpthev pusher oscillates. It will be Aobserved by referenceto Figure lof the drawingsthatlthe flexible fingers I6 comprising the;` yieldable wall ,I4 wh,ich defines theY front portion of the throatway I2 extend'downwardly to aV point immediately. above the path of travely of the arcuat@ plate lit Y., Y, Y., Y Y,

' Acrankarm'ZI) isgsecured to andY depends from the vpusher'I, YI9 and has a driving pin 2l proje'cting laterally Yfrom the lower end thereof. The driving pin 2L extends through a longitudinal slot 22 in the front end of a ldriving link23, the effective length of the ,slot 22being variable through the .medium of. a Screw 24 adiustalvlyY mounted in.k a bearingr25carried by the link. AV'I'hepurposek offthis ,adjustment `of the slot length VVwilllloe described hereinafter.- .At its other end, the link23 is connected to 'a crank pin 26 which projectsY laterallyfroma ratchet ,wheel 21 having avrelatively large drivingsurface or periphery V2t! and which` isV freely rotatable, on a shaft or bearing pin V29 vrigidly, supportedas at 30, on the housing 9*. 71tfwill`be obvious that when rotation is imparted tothe wheel 21, this rotary motion will be transmitted lin the form of oscillatory motion to the pusher I,8 I9'throughthe crank and link connections` 26, 23, 2l and20. n

Forr imparting the desired rotary motion to the wheel 21there is providedV a driving arm 3| which is oscillata'bly mounted, as atv 32on the shaft 29,

and this arm has a1 driving pawl 33 lpiyoted thereon, as at 34, 'in position for engagingA in driving relation with the periphery 28,` of the wheel 21. The Vpawl, is disposed in the manner best illustrated in Figure 4 of the drawings so that it will dragjfreelyn over the wheel periphery when the arm, is imovedltothe left; as viewed in Figures'l and 4, and will engage in driving'relation with saidv periphery when the arm is moved to the right therebytoimpart' rotation in a clockwise direction to saidwheel. rIfhe arm 3|Y is slotted, as4 at 35, to adjustablyreceive a shoulder bolt 36V which is attached to the rvfront end of a. driving link 31. Theother end of the link 31 is attached to a crankpin 38 which projects laterally from a driving diskr 39 carried by the shaft 40 of a motor 4I rigidly" supported, as at 42, upon the housing 19. It Vv villloe obvious that rotary motion of lthe disk 3.9v Vwill be transmitted in the form of oscillatory' movementto the arm 3l through the crank and link connections 38, 31V and 36.

VA fuel supporting and feed distributing'or spreadingplateAS Vis hingedly attached, as at 44, tothe pusher plate I8, land this hingedlyfmounted plate is. generally at in shape and has its front the plate 43 rests ingenerally horizontal position means mounted on the housing 9, and when the pusher I8, I9 is inI its forwardly projected or fuel feeding and spreading position, the, plate 43 is supported on a similar cross rod or supporting means 41 in the ydownwardly and forwardly inclined position illustrated in full lines in Figure 1 fori effectively distributing the fed fuel charge over the Yfire bed.

YB'y mounting the plate 43 in the manner stated and positioning thev supporting elements 46, 41

in the mannerhereinbefore described, when the pusher I8, I9 is in its retracted position illustrated in dotted lines in Figure 1, thefrontplate I8 and uthe plate 43 together form a pocket or fuel supporting shelf at the bottom of the fuel "discharg- ,ing throat I2, and the plate 43 lies in generally 'horizontal position beneath the lower extremities of the flexible fingers I6.V VWhen the pusher is l moved to its forward position the plate 43 swings forwardly and downwardly, under `control'of the supporting elements 46, 41, to the fuel charge spreading position illustrated in full'lines in Figure l. It will also :be observed by reference to the'dotted. une illustration in Figure 1 that when I2 being ignited by radiant heat from the re bed in the furnace.

By reason of the provision of theyieldable wall or gate I4 and the relation thereof to the hopper discharge throat I2 and the furnace fuel chargingopening I0, the feeding of fuel charges can be accomplished without any danger of jamming of parts by reason ofengagement of the pusher with coal lumps or any foreign particles contained in the fuel, movement of which is being obstructed by contact of unyielding surfaces. In other Words, should.V the pusher move forwardly a charge of fresh fuel including one or more large lumps, and possibly a railroad spike, astone or a similar bit lof foreign matter, Vthe wall or gate I4 or portions thereof are free to yield and permit passage f of such lumps lor particles without jamming of the parts and without free and uncontrolled outpouring Vofthe fuel particles of lesser sizes at opposite sides of a jammedy coal lump or other large particle.

It is desired that the pusher I8,`I9 shall have a constant, that is, an unvarying forward stroke limit, this limit-being the full line position illustrated in Figure 1 of the drawings. It is also desirable that the length of the stroke movement imparted to the pusher I8, `I9 be variable so that the amount of each fuel charge fed into the furnace at each forwardr movement of the 'pusher Figure-l of the drawings.

in Width than the openin the esecuve length ofthe slot 22 in the link motion has been taken up and the adjustable screw 24 engages the pin 2l. By adjusting the position of the shoulder bolt 3S in the driving arm slot 35, the degree of the individual increments of movement imparted by the arm 3l to the wheel 21. can be varied. i

Itis to be understood that in adoor feed stoker mechanism of the nature` herein disclosed a satisfactory control can *bev effected with a simple thermostat. When the thermostat calls for heat the motor lily is put into operation to impart step rotation to the wheel 21 and reciprocation rto the pusher it. I9 in the manner hereinbefore described, and the motor continues to operate until a sufficient amount of fresh fuel has been fed to the re to build up heat sufficient to turn off the thermostat, It should also be understood that other conventional stoker controls can be used. In addition to the usual thermostat and bonnet control arrangement, a suitable. mechanism may be employed which provides a certain feed timing during periods when the house and thermostat are overheated. The controls which have been mentioned are conventional, however, and since they in themselves form no part of the present invention, further detailed disclosure thereof is deemed unnecessary herein.

It will be obvious by reference to Figure 1 of thedrawings that when the pusher I 8, VI 9fis in the retracted position illustrated in dotted lines, the plate or shelf if will support the fuel in the hopper discharge throat IZ and effectively close the firing opening ill so as to protect the fuel supply fromvradiant heat. As the pusher I8, I9 moves forwardly on a fuel charging and distributing stroke, the plate d3 will retain its generally hori-` zontal position until a certain point is reached late in the forward movement of the pusher and the plate t3 hingedly mounted thereon. When this'point is reached, the plate 43 will fall rapidly over the rod 19,6 andv onto the rod 4l lintothe position illustrated in fulllines in Figure 1 and in .so doing will effectively distribute the fuel charge on the fire bed.

It is to be understood that the details of structure and arrangement of parts may be variously7 changed and modified without departing from the spirit and scope fof the invention.

We claim:

l.. A st'oking apparatus for a furnace having a fire bed; and a firing door opening; a firing door, a housing carried by said door, a fuel hopper supported by the housing and having a gravity discharge throat normally open for delivery of fuel from said hopper and disposed in said housing, said ydoor and housing having registering openings therein adjacent the throat and communicating with the interior of the furnace at an elevation above the fire bed so that fuel discharged through said throat and delivered through said openings will'fall by gravity onto said lire bed, a yieldable uprightly disposed wall in part defining the porn tion of the normally open discharge throat nearest said openings and yieldable yso as to be displaceable byfuel lumps or large particles of foreign matter to permit passage thereof toward said openings;` and a 'fuel feeding pusher reciprocableacross the throat close beneath `said uprghtly disposedyieldable wall and effective upon each forward stroke to deliver a charge of fuel from the throat through said openings and into the furnace,

2. A structure as defined in claim 1 in which the pusher is oscillatably mounted and includes a substantially arcuate plate. portion the arc of Which'is struck approximately from the center about which the pusher oscillates and which plate is effective in one position of the pusher to close the throat, and in which the yieldable wall comprises a supporting bar and a plurality of closely spaced flexible fingers extending down close t0 but short of contact `with said arcuate plate.

3. A structure as defined in claim 1 in which the pusher is oscillatably mounted and includes a substantially arcuate plate portion the arc of which is struck approximately from the center about which the pusher oscillates and which .plate is effective in one position of the pusher to close the throat, and in which there is included a fuel supporting and distributing plate attached to the pusher, and means for supporting said supporting and distributing plate in position for forming with the pusher a pocket for receiving and supporting fuel when the pusher is retracted, said supporting and distributing plate being movable with the pusher, when the latter is projected to deliver a charge of fuel into the furnace, to a position for aiding in distributing the charge of fuel 'over the fire bed in the furnace.`

4. A structure as defined in claim 1 in which the pusher is oscillatably mounted and 'includes a substantially arcuate plate portion the arc of kwhich is struck approximately from the center about which the pusher oscillates and which plate is effective in one position of the pusher to close the throat, andin which there is included a fuel supporting and distributing plate pivotally at` tached to the pusher, and means movably supporting andV guidingV said supporting and dis-r tributing `plate on the housing `in such manner that it assumes a generally horizontal position beneath the yieldable wall for supporting fuel when the pusher is retracted and moves into a forwardly and downwardly inclined position as the pusher is moved to its projected position thereby to aid in distributing the charge of fuel over the fire bed in the furnace. y

5. In a furnace wherein is provided a casing y y having a fire bed supporting means and an open- 56" ing through which fuel can be fed onto the fire bed, stoking means including a hopper having a gravity discharge throat, means supporting said hopper in position for placing the throat adjacent said opening, a fuel feeding pusher, means reciprocably mounting said pusher in position for being reciprocable across the discharge throat for feeding fuel charges through said opening into the fire bed and effective in its forwardly pro- J'ected position to close said throat, a motor, a crank driven by the motor, a crank disk, ratchet and pawl driving connections between the crank kand the crank disk, and a link connected at one end to the crank pusher,

6, In a furnace wherein is provided a casing having a fire hed supporting means and an opendisk and at its other end to the ing through which fuel can be fed onto the lirevv bed, stoking means including a hopper having a,

gravity discharge throat, means supporting said hopper in position for placing the throat adjacent said' penin'ga fuelfeeding pusher, means re#` ciprocably mounting'said pusher in position for being reciprocable across the discharge throat for feeding fuel charges through said opening into the fire bed and effective in itsforwardly projected position to close said throat, `a motor, a crank driven by the motor, a crank disk,'ratchet and pawl driving connections between the crank and the crank disk, and alink connected at one end to the crank disk and at its other end to thev pusher, one of said link end connections con,-v stituting'an adjustable lost motion connection. 1

7. In a furnace wherein is provided afcasing having a fire bed supporting means ,and an opening through which fuel can be fed ontothe re bed, stoking means including a hopper having a gravity discharge throat, means supporting the hopper in position for placing the throat adjacent said opening, a fuel feeding pusher, meansoscillatably mounting said pusher in position for being oscillated across said throat for feeding fuel through said opening, a driving motor including a driven shaft, acrank arm projecting fromv the pusher, driving crank means on said shaft, and power transmitting connections between the crank arm and said driving crank means whereby the rotary movement of the shaft will be transmitted in the form of oscillatory movement of the pusher.

8. In a furnace wherein is provided a casing having a fire bed supporting means and an opening through which fuel can be fed onto the lire bed," and a combination closure door and'stoking means' mountable and removable as a unit over said opening and-comprising a hingedly mounted closure door, a housing carried by said door, a fuel hopper supported by the housing and having a gravity discharge throat normally open for delivery of fuel from said hopper and disposed in said housing, said door and housing having registering openings'therein adjacent thethroat and communicating with the interior of the furnace, a yieldable uprightly disposed wall in part defining the portion of the normally open discharge throat nearest said openings and yieldable so as to be ldisplaceable by fuel lumps `or large particles of foreign matter to permit passage thereof toward said openings, and a fuel feeding pusher reciprocable across thel throat close beneath said uprightly disposed yieldablewall and effective upon each forward stroke to deliver a charge of fuel from the throat through said openings and into ther furnace.

9. In a, furnace wherein is provided a casing having a re bed supporting means and an open; ing through which fuel can be fed onto the fire bed,rand a combination closure door and stoking means mountable and removable as a unit over said opening and comprising a, hingedly mounted closure door having an opening therein registering with said casing opening, a'hopper having a gravity discharge throat registering openings, a fuel feedingpusher reciproeably mounted beneath'said throat and including a plate portion effective in one position toclose the throat, a fuel supporting anddistributing plate attached to therpusher and xedly mounted supporting means on which said sup,V porting and distributing plate rests and effectiveVV to place said plate in a generally `horizontal position for receiving and supporting fuel when the pusher `is retracted and to place said plate in a forwardly and downwardly inclined position when the pusher is projected so as to deliverrand disi 8" tribute 'the supported bed inthe furnace.

10. In a furnace wherein is provided a casing having a fire bed supporting means and an open-V ing through which fuel can be fed onto the fire bed, stoking means including a hopper having a gravity discharge throat, means supporting said n hopper in position for placing said throat adjacent said openinga fuel feeding pusher, means reciprocably mounting said pusher beneath said' throat, Ysaid pusher including a plate portion effective in one position of the pusher to close the throat a fuel supporting and distributing plate, and means for supporting said supporting and distributing plate in. position for forming with'the pusher a pocket for receiving and supporting fuel whenthe pusher is retracted, said supporting and distributing plate being attached Y to the pusher and movable therewith when the pusher is projected to deliver a Ycharge of fuel into the furnace to a position. for aiding in the distribution of the charge of fuel over the fire bed in the furnace.

11. In a furnace wherein is provideda casing having a re bed supporting means and an opening through which fuel can be fed onto the fire bed, stoking means including a hopper having a gravity discharge throat, means supporting said hopper in position for placing said Wthroat adjacent said opening, a fuel feeding pusher, Vmeans reciprocably mounting said pusher in generally horizontal position beneath said throat, said pusher includingV a plate portion effective in one position of the pusher to supporting and distributing plate, and means for supporting said supporting and distributing plate in position for formingwith the pusher a' pocket for receiving and supporting fuel when the pusher is retracted, said supporting and distributing platerbeing attached'to the pusher and movable therewith when the pusher is projected to deliver a 'charge of fuel into the furnaceto a position for aiding in the distribution of the. charge of fuel overthe fire bed in the furnace, said pusherV also including a front plate disposed generally uprightly and connected at the foremost edge portion of the pusher plate portion, and said fuelv supporting and distributing plate having its place vof attachment with the pusher at a point on said front plate spaced downwardly Vfrom the connecz ,ing through which fuel can be fed onto the fire bed, stoking means including a hopper having a gravity discharge throat, means supporting said disposed adjacent said i hopper intposition for placing said throat adja-V cent said opening, a fuel feeding pusher means oscillatably mounting said pusher beneath said throat, said pusher including a substantially arcuate plate portion the arc of which is struck approximately from the center about which the pusher oscillates and which substantially arcuate plate is effective in one position tok close the throat, a fuel supporting and distributing plate,

and means for supporting said supporting and distributing plate vin position for forming with the pusher a pocket for receiving and supporting fuel when the pusher is retracted said supporting and distributing plate being hingedly attached to the pusher and lmovable therewith when the pusher is projected to deliver a charge of Yfuel into the furnace to a position for aiding inthe distribution of -the charge vof fuel over the re bed Vin the furnace, said pusher also VVincluding aY fuel charge over the fire close the throat, a fuel `front plate connected at the foremost edge portion of the substantially arcuate plate and projecting substantially radially with respect to the center about which the pusher oscillates, and said fuel supporting and distributing plate having its hinge attachment with the pusher at a point on said front plate spaced downwardly from the connection of said front plate with the substantially arcuate plate, and said distributing plate.

supporting means being disposed to support the distributing plate in such manner that it will assume a generally horizontal position beneath the throat when the pusher is retracted and will move into a forwardly and downwardly inclined position over said supporting and guiding means as the pusher is moved to its projected position.

13. In a furnace wherein is provided a casing having a fire bed 'supporting means and an opening through which fuel can be fed onto the re bed, stoking means including a hopper having a gravity discharge throat, means supporting said hopper in position for placing the throat adjacent said opening, a fuel feeding pusher, means reciprocably mounting said pusher beneath said throat, said pusher including a plate portion effective in one position to close the throat,a fuel supporting and distributing plate attached to the pusher, and xedly mounted supporting means on which said supporting and distributing plate rests and effective to place said plate in a generally horizontal position for receiving and supporting fuel when the pusher is retracted and to place said plate in a forwardly and downwardly inclined position when the pusher is projected so as to deliver and distribute the supported fuel charge over the re bed in the furnace.

14. A structure as dened in claim in which the fuel supporting and distributing plate is said power transmitting connections include al hingedly attached to the pusher, and in which the supporting and distributing plate supporting means is disposed close beneath the plate hinge attachment when the pusher is projected so that the fuel supporting and distributing plate willl fall rather rapidly to its forwardly and downwardly inclined position just as the pusher approaches its projected position thereby to facilitate distribution of each fuel charge over the re bed in the furnace.

15. A structure as dened in claim 10 in' which there is included means for so positioning the fuel supporting and distributing plate when said plate is retracted and in the opening through which fuel can be fed onto the fire bed that it closes said opening and protects fuel in the hoplper discharge throat from the direct action of ratchet wheel having a, crank pin projecting therefrom, ratchet and pawl driving connections between the shaft borne crank and said ratchet wheel, and a link connected at one end to the crank pin of the ratchet wheel and at its othery end to the pusher crank, one said link end connection constituting an adjustable lost motion connection.

`WILLIAM P. BIDDLE, Jn. HUGH W. SANFORD, JR, 

